Probiotic composition comprising one or more probiotic microorganisms, a carrier which will function to transport the one or more probiotic microorganisms to the large bowel or other regions of the gastrointestinal tract of an animal, the carrier comprising a modified or unmodified resistant starch or mixtures thereof, which carrier acts as a growth or maintenance medium for microorganisms in the large bowel or other regions of the gastrointestinal tract, and an oligosaccharide. Method of increasing the number of probiotic or resident microorganisms in the gastrointestinal tract of an animal comprising providing to the animal the probiotic composition.